Such tools, especially provided with a plurality of cutting inserts distributed around the periphery of the tool and distributed along the longitudinal center axis of the tool, are expensive and complicated to manufacture. These tools include a large number of seats for the cutting inserts. If such a seat is broken, in the worst case, the entire tool has to be replaced. Especially those cutting inserts and seats that are situated at the front end of the tool are subjected to great stresses during use of the tool.
This problem can be solved by the tool being divided into at least two coupled tool parts, a main body connected with the shaft of the tool and an end body that is interconnected with the main body in a detachable way. If a seat of a tool part is broken, it is enough to exchange this tool part. Such dividable tools are shown in U.S. Pat. No. 5,800,098 and in U.S. Pat. No. 5,551,811.
U.S. Pat. No. 5,551,811 shows a tool for cutting machining, including a primary tool part, a secondary tool part and a shaft part that is formed for fixing in a machine tool. The primary tool part has a primary connecting surface and an opposite surface toward the shaft part as well as a recess that extends from the primary connecting surface toward the opposite surface. The primary tool part has a wall section between a bottom surface of the recess and the opposite surface. The secondary tool part has a secondary connecting surface and a protuberance that extends axially from the secondary connecting surface and, in a mounted state, into the recess.
The protuberance has an end surface that, in the mounted state, faces the bottom surface. A relatively long fixing screw connects, by a contractive force, the wall section with the protuberance in the mounted state. A center axis extends in a longitudinal direction of the tool through the primary tool part and the recess thereof, through the secondary tool part and the protuberance thereof as well as through the shaft part. The primary and secondary tool parts comprise respective seats formed for the receipt of a cutting insert each.
U.S. Pat. No. 5,607,263 shows another cutting tool having a detachable tool head wherein the cutting inserts are an integrated part of the cutting head.
However, there are several problems with dividable tools, especially in the coupling that connects the primary tool part with the secondary tool part. The temperature differences that arise between the tool parts during use of the tool may lead to dimensional changes and the primary tool part moving in relation to the secondary tool part. The stresses and vibrations that occur when using the tool may lead to the utilized coupling elements, such as fixing screws or the like, coming loose. The coupling between the tool parts is often bulky and interferes with the possibility of arranging other tool components on or in the tool, for instance, a damping mechanism. The mounting and dismounting of the tool parts are a complicated and time-consuming working operation. The manufacture of the tool is complicated by the fact that it includes two tool parts each one of which requires a special design for the interconnection of the tool parts.
An object of the invention is to provide a tool of the type indicated, by which the above mentioned problems, or at least some of the above mentioned problems, can be obviated or reduced.